1. Field of the Invention
The present invention relates to a fiber reinforced cement composition using a hydraulic inorganic material such as cement, products thereof and a manufacturing process thereof.
2. Description of the Related Art
The following description sets forth the inventor's knowledge of related art and problems therein and should not be construed as an admission of knowledge in the prior art.
Hitherto, for manufacturing process of fiber reinforced cement product using a hydraulic inorganic material such as cement, when the specific gravity of fiber reinforced cement product is high by adding a lot of powder, freezing and fusion resistance and bending strength improve basically.
But, if the product is hard by high specific gravity thereof, there is a problem in installation property such as nail performance.
Thus, nail performance is improved by adding woody reinforcement such as pulp in large quantities.
But when pulp is added in large quantities, noncombustible performance of product is lost, freezing and fusion resistance deteriorates again, too.
Thus, a special woody reinforcement such as needle-leaves-tree kraft pulp has recently been used as the woody reinforcement, and U.S. Patent Application Publication No. 2004/168615 discloses that quantity of pulp addition is held down using two kinds of particular pulp.
And, for reason of physical property enhancement, about powder rather than woody reinforcement, various lightweight aggregates addition is examined.
For example, in Japanese Patent No. 3374515, it is disclosed that the amount of not less than 5% by mass and not more than 30% by mass of vermiculite adds in cement molding composition.
In Japanese unexamined laid open patent publication No. 2000-264701, it is disclosed that wood fiber which specified average fiber length and average fiber width adds in matrix, furthermore, the amount of not less than 18% by mass and not more than 60% by mass of expanded inorganic material such as expanded perlite adds in matrix.
And, in Japanese patent Publication No. H08-32603, it is disclosed that lightweight cement molding composition for extrusion comprising cement, lightweight aggregate, inorganic aggregate, organic fiber, cellulose type additive, in which lightweight aggregate is fly ash which has average particle size of not more than 2 mm, has a bulk specific gravity of not less than 0.1 and not more than 0.4, and inorganic aggregate comprising (A) and (B), in which inorganic aggregate (A) is spherical aggregate which has a particle size of not less than 1 μm and not more than 100 μm selected out of fly ash and spherical calcium silicate hydrates, in which inorganic aggregate (B) is a ultra-fine particle aggregate which has a particle size of not less than 0.01 μm and not more than 0.5 μm selected out of micro-silica, silica fume, natural pozzolan, diatomaceous earth, silica flower, aerosol.
In the present invention, it is examined that a particle size of aggregate as well as a kind of aggregate, to get the fiber reinforced cement product having excellent properties in nail performance and freezing and fusion resistance.
The description herein of advantages and disadvantages of various features, embodiments, methods, and apparatus disclosed in other publications is in no way intended to limit the present invention. For example, certain features of the preferred embodiments of the invention may be capable of overcoming certain disadvantages and/or providing certain advantages, such as, e.g., disadvantages and/or advantages discussed herein, while retaining some or all of the features, embodiments, methods, and apparatus disclosed therein.